Various systems exist for connecting fastener elements (e.g., pedicle screws, iliac screws, cervical screws) to bones for the purpose of spinal (e.g., vertebral, iliac, cervical) fixation. Such systems may use a plurality of screws fitted in bodies, wherein a plurality of bodies are aligned using a mounting rod.
A spinal fixation system may comprise several components with various degrees of stability or various degrees of movement between the components themselves or between the components and the bones to which they are affixed. For example, the connection between the bones and the fastener may have a degree of stability. Greater stability may help promote a more secure system and a more secure fixation for multiple segments of the spine. However, overly rigid or inflexibly positioned fastener elements may prevent the mounting rod from being aligned properly along a plurality of spinal elements (e.g., vertebrae).
For surgical proceedings, the components intended to be used for the spinal fixation system may often be preselected. Such selection may be made based on a number of factors such as the particular dimensions of the components and the anatomical location for the fixation of the system. However, sometimes during the actual surgery, the preselected components may be determined to not actually be ideal. This may be the case when the preselected components allow for too much or not enough movement or flexibility of the fastener elements.